scholarly journals Neuromuscular efficiency of the knee joint muscles in the early-phase of strength training: effects of antagonist’s muscles pre-activation

Motricidade ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 24-32
Author(s):  
Euler Alves Cardoso ◽  
Frederico Ribeiro Neto ◽  
Wagner Rodrigues Martins ◽  
Martim Bottaro ◽  
Rodrigo Luiz Carregaro
Keyword(s):  
Knee Flexion ◽  
Controlled Trial ◽  
Rectus Femoris ◽  
Training Group ◽  
Knee Extension ◽  
Effect Sizes ◽  
Randomized Controlled ◽  
Knee Extension Exercise ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle

It was our objective tTo compare the neuromuscular efficiency (NME) adaptations between resistance exercise methods (with and without pre-activation of the antagonist’s muscles) after six-weeks training. This randomized controlled trial assigned forty-nine men (mean age 20.9 ± 2.2 years; height 1.80 ± 0.1 m; body mass 75.0 ± 8.2 kg) into two groups: 1) Reciprocal Training group (RT, concentric knee flexion immediately followed by concentric knee extension at 60°.s-1); and Conventional Training (CT, concentric knee extension exercise). Both training adopted three sets, 10 repetitions at 60°.s-1, 2 days/week for 6 weeks. NME of knee extension and flexion were assessed pre and post-training. The groups were similar at baseline, for all variables. We found significant effects on NME only for the rectus femoris muscle in the RT group (ES = 0.31; 95%CI [0.30-0,92]; p<0.01). There were no significant differences at NME pre- and post-training in CT and Total Work did not differ between groups. Reciprocal training provided better neuromuscular efficiency, but effects were limited to the rectus femoris muscle. The small effect sizes suggest caution in the results.

Intramuscular differences in shear modulus of the rectus femoris muscle during passive knee flexion

2021 ◽  
Vol 121 (5) ◽  
pp. 1441-1449
Author(s):  
Taiki Kodesho ◽  
Keigo Taniguchi ◽  
Takuya Kato ◽  
Masaki Katayose
Keyword(s):  
Shear Modulus ◽  
Knee Flexion ◽  
Rectus Femoris ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle

Two Components of Motor Time: The Tension Lag and the Tension-Developing Phase

1984 ◽  
Vol 59 (3) ◽  
pp. 907-912 ◽  
Author(s):  
R. Nakamura ◽  
H. Nagasaki ◽  
I. Tsuji
Keyword(s):  
Early Phase ◽  
Rapid Development ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Isometric Tension ◽  
Lag Phase ◽  
Motor Time ◽  
Normal Men ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle

Motor time (MT) of the rectus femoris muscle for knee extension under loading on the leg with different weights and latency of isometric tension from the onset of electromyographic activities of the muscle were examined in 7 normal men. MT was linearly related to weights-loaded, indicating that the rate of rapid development of tension was almost linear even in its early phase. MT without a load obtained by calculation using the regression equation and the estimated weight of the leg and foot coincided with latency of isometric tension. It is assumed that MT is composed of two consecutive phases, a tension-lag phase and a rapid tension-developing phase.

scholarly journals One Session Effects of Knee Motion Visualization Using Immersive Virtual Reality in Patients with Hemophilic Arthropathy

2021 ◽  
Vol 10 (20) ◽  
pp. 4725
Author(s):  
Roberto Ucero-Lozano ◽  
Raúl Pérez-Llanes ◽  
José Antonio López-Pina ◽  
Rubén Cuesta-Barriuso
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Joint Damage ◽  
Rectus Femoris ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Post Intervention ◽  
Specific Protocol ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle

(1) Background: Hemophilic knee arthropathy is characterized by a loss of muscle mass and decreased strength of the quadriceps muscle. The visualization of movement aims to favor the recruitment of the motor system in the same premotor and parietal areas, as would happen with the active execution of the observed action. The aim was to evaluate changes in quadriceps activation in patients with hemophilic knee arthropathy following immersive VR visualization of knee extension movements. (2) Methods: We recruited 13 patients with severe hemophilia A and knee arthropathy. Patients underwent a 15 min session of immersive VR visualization of knee extension movements. The quadriceps muscle activation was evaluated by surface electromyography. (3) Results: After the intervention, there were no changes in the muscle activation of vastus medialis, vastus lateralis, or rectus femoris muscles. There was a large effect size of changes in rectus femoris muscle activation. Age and knee joint damage did not correlate with changes in quadriceps activation. Dominance, inhibitor development, and type of treatment were not related with post-intervention muscle activation. (4) Conclusions: A session of immersive VR visualization of knee extension movement does not modify quadriceps muscle activation. A specific protocol for patients with hemophilic knee arthropathy may be effective in improving the activation of the rectus femoris muscle.

Efficacy of a Second-Grade Science Program: Increasing Science Outcomes for All Students

2021 ◽  
pp. 074193252198909
Author(s):  
Christian T. Doabler ◽  
William J. Therrien ◽  
Maria A. Longhi ◽  
Greg Roberts ◽  
Katherine E. Hess ◽  
...  
Keyword(s):  
Science Achievement ◽  
Controlled Trial ◽  
Science Instruction ◽  
Effect Sizes ◽  
Second Grade ◽  
Guided Inquiry ◽  
Randomized Controlled ◽  
Second Grade Students ◽  
Cluster Randomized ◽  
Business As Usual

This study, which was reviewed through the Registered Report process, examined the initial efficacy of the Scientific Explorers program (Sci2) on second-grade students’ science achievement. Sci2 is grounded in the growing body of empirical research on science instruction, embedding principles of explicit instruction within a guided inquiry-based design framework. Eighteen second-grade classrooms were randomly assigned to treatment or control conditions. A cluster randomized controlled trial was employed, with 294 students nested within classrooms and classrooms nested within condition. The Sci2 program was implemented for a total of 10 lessons (5 hr) in treatment classrooms, whereas control classrooms provided business-as-usual science instruction. Overall treatment effects were observed on three of four science outcome measures. The reported effects were moderate to large, with effect sizes (Hedges’ g) ranging from 0.48 to 0.94. Moderation analyses indicated that science knowledge at pretest did not moderate Sci2’s effects. Implications for practice and research are discussed.

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